J/ApJ/750/76 r-process peaks elements in HD 160617 (Roederer+, 2012)
Detection of elements at all three r-process peaks in the metal-poor star
HD 160617.
Roederer I.U., Lawler J.E.
<Astrophys. J., 750, 76 (2012)>
=2012ApJ...750...76R 2012ApJ...750...76R
ADC_Keywords: Atomic physics ; Equivalent widths ; Stars, metal-deficient ;
Stars, halo
Keywords: atomic data - nuclear reactions, nucleosynthesis, abundances -
stars: abundances - stars: individual: (HD 160617) -
stars: Population II
Abstract:
We report the first detection of elements at all three r-process peaks
in the metal-poor halo star HD 160617. These elements include arsenic
and selenium, which have not been detected previously in halo stars,
and the elements tellurium, osmium, iridium, and platinum, which have
been detected previously. Absorption lines of these elements are found
in archive observations made with the Space Telescope Imaging
Spectrograph on board the Hubble Space Telescope. We present
up-to-date absolute atomic transition probabilities and complete line
component patterns for these elements. Additional archival spectra of
this star from several ground-based instruments allow us to derive
abundances or upper limits of 45 elements in HD 160617, including 27
elements produced by neutron-capture reactions. The average abundances
of the elements at the three r-process peaks are similar to the
predicted solar system r-process residuals when scaled to the
abundances in the rare earth element domain. This result for arsenic
and selenium may be surprising in light of predictions that the
production of the lightest r-process elements generally should be
decoupled from the heavier r-process elements.
Description:
We use ground-based optical spectra of HD 160617 from several
telescope and instrument combinations. Some spectra were retrieved
from the European Southern Observatory (ESO) Science Archive Facility.
A spectrum obtained with the Ultraviolet and Visual Echelle
Spectrograph (UVES) on the Very Large Telescope (VLT) Kueyen at Cerro
Paranal, Chile covers the wavelength range 3055-3870Å at R∼40000
with S/N ranging from 100 to 400 per pixel. A spectrum obtained with
the High Accuracy Radial velocity Planet Searcher (HARPS) on the ESO
3.6m Telescope at La Silla, Chile, covers the wavelength range
3780-6910Å at R∼115000 with S/N ranging from 150 to 300 per pixel.
Another spectrum was retrieved from the Keck Observatory Archive. This
spectrum was obtained with the High Resolution Echelle Spectrometer
(HIRES) on the Keck I Telescope at Mauna Kea, Hawai'i. It covers the
wavelength range 4395-6770Å at R∼49000 with S/N ranging from 130 to
300 per pixel.
Objects:
-------------------------------------------------------
RA (2000) DE Designation(s)
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17 42 49.32 -40 19 15.5 HD 160617 = TYC 7889-1175-1
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table4.dat 50 33 Hyperfine structure line component patterns for
75As I lines
table8.dat 58 24 Hyperfine structure and isotopic line component
patterns for Cd II lines
table10.dat 58 26 Hyperfine structure and isotopic line component
patterns for Yb II lines
table12.dat 58 12 Hyperfine structure and isotopic line component
pattern of the 1942 Angstrom line of Hg II
table13.dat 40 274 Equivalent width measurements
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See also:
J/A+A/442/961 : Lithium content of the Galactic Halo stars (Charbonnel+, 2005)
J/A+A/440/321 : Chemical abundances in 43 metal-poor stars (Jonsell+, 2005)
J/AZh/82/453 : Catalogue of spectroscopic abundances in stars (Borkova+, 2005)
J/PASJ/57/65 : CNO abundances of solar-type stars (Takeda+, 2005)
J/A+A/415/993 : FeII, ZNI and SI abundances on halo stars (Nissen+, 2004)
J/A+A/390/235 : OI & FeII equivalent widths in metal-poor stars (Nissen+ 2002)
J/A+A/354/169 : Metal-poor field stars abundances (Gratton+, 2000)
J/AJ/117/981 : Estimation of stellar metal abundance. II. (Beers+, 1999)
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.3 cm-1 sig Center-of-Gravity wavenumber σ (1)
11- 19 F9.4 0.1nm lam0 [1890/1991] Center-of-Gravity vacuum
λ wavelength (Å) (1)
21 I1 --- Fupp Component upper level F or total angular momentum
23 I1 --- Flow Component lower level F or total angular momentum
25- 32 F8.5 cm-1 dsig Component offset wavenumber σ with respect
to Center-of-gravity Wavenumber (1)
34- 42 F9.6 0.1nm dlam Component offset Wavelength with respect to
Center-of-gravity Wavelength (Å)
44- 50 F7.5 --- Str Component strength normalized to sum to one
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Note (1): σ and λ are from Howard & Andrew (1985OSAJB...2.1032H 1985OSAJB...2.1032H)
with component positions relative to those values from HFS constants
of Pendlebury & Smith (1964PPS....84..849P 1964PPS....84..849P) and Bouazza et al.
(1987ZPhyD...7...33B 1987ZPhyD...7...33B).
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Byte-by-byte Description of file: table8.dat table10.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.3 cm-1 sig Center-of-Gravity wavenumber σ (1)
11- 19 F9.4 0.1nm lam [2116/2266] Center-of-Gravity air wavelength
λ (Å) (1)
21- 23 F3.1 --- Fupp Component upper level F or total angular momentum
25- 27 F3.1 --- Flow Component lower level F or total angular momentum
29- 36 F8.5 cm-1 dsig Component offset Wavenumber with respect to
Center-of-gravity Wavenumber (1)
38- 46 F9.6 0.1nm dlam Component offset Wavelength with respect to
Center-of-gravity Wavelength (Å)
48- 54 F7.5 --- Str Component strength normalized to sum to one
56- 58 I3 --- Iso Isotope
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Note (1): σ and λ are from Burns & Adams (1956JOSA...46...94B 1956JOSA...46...94B)
in table 8 or from Martin et al. (1978aelr.book.....M 1978aelr.book.....M) in table 10 for
a S.S. isotopic mix using the index of air (Peck & Reeder,
1972JOSA...62..958P 1972JOSA...62..958P) with component positions relative to those values.
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Byte-by-byte Description of file: table12.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.3 cm-1 sig Center-of-Gravity wavenumber σ (1)
11- 19 F9.4 0.1nm lam0 [1942/1943] Center-of-Gravity vacuum wavelength
λ (Å) (1)
21- 23 F3.1 --- Fupp Component upper level F or total angular momentum
25- 27 F3.1 --- Flow Component lower level F or total angular momentum
29- 36 F8.5 cm-1 dsig Component offset Wavenumber with respect to
Center-of-gravity Wavenumber (1)
38- 46 F9.6 0.1nm dlam Component offset Wavelength with respect to
Center-of-gravity Wavelength (Å)
48- 54 F7.5 --- Str Component strength normalized to sum to one
56- 58 I3 --- Iso Isotope
--------------------------------------------------------------------------------
Note (1): σ and λ are form Sansonetti and Reader
(2001PhyS...63..219S 2001PhyS...63..219S) for a S.S. isotopic mix with component
positions relative to those values.
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Byte-by-byte Description of file: table13.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.2 0.1nm lam [3321/6768] Wavelength λ (Å)
9 A1 --- f_lam [a] line rejected (1)
11- 15 A5 --- Ion Species identification
17- 21 F5.3 eV ExPot [0/5.1] Excitation potential
23- 28 F6.3 [-] log(gf) [-5/0.7] Log of the oscillator strength
30- 34 F5.1 0.1pm EW [1.7/147.6] Equivalent width (mÅ)
36- 40 A5 --- Inst Instrument used (HARPS, HIRES or UVES)
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Note (1):
a = Equivalent width measured but line rejected from abundance
computation; see Section 4.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 04-Dec-2013